Electric discharge lamp having a fill including niobium pentaiodide complexed with an inorganic oxo-compound as the primary active component

ABSTRACT

An electric discharge device comprising a sealed lighttransmissive envelope; and a fill within the envelope, the fill including, as the primary light-emitting material, niobium pentaiodide complexed with an inorganic oxo-compound, particularly an oxytriiodide of a Group VA element or an oxydiiodide of a Group VIA element.

United States Patent 1 Silver July 24, 1973 1 ELECTRIC DISCHARGE LAMP HAVING A FILL INCLUDING NIOBIUM PENTAIODIDE COMPLEXED WITH AN INORGANIC OXO-COMPOUND AS THE PRIMARY ACTIVE COMPONENT [75] Inventor: II. Graham Silver, Kings Point, NY.

[73] Assignee: General Telephone & Electronics Laboratories Incorporated, New York, NY.

[22] Filed: May 5, 1972 [21] Appl. No.: 250,648

[52] US. Cl 313/184, 313/225, 313/227, 313/229 [51] Int. Cl. H0lj 61/18 [58] Field of Search 313/225, 229, 184, 313/227 [56] References Cited UNITED STATES PATENTS 3,234,421 2/1966 Reiling 313/225 X 3,514,659 5/1970 Gungle et al. 313/184 3,521,110 7/1970 Johnson 313/229 X Primary Examiner Palmer C. Demeo Attorneylrving M. Kriegsman [57] ABSTRACT 22 Claims, 1 Drawing Figure ELECTRIC DISCHARGE LAMP HAVING A FILL INCLUDING NIOBIUM PENTAIODIDE COMPLEXED WITH AN INORGANIC OXO-COMPOUND AS THE PRIMARY ACTIVE COMPONENT BACKGROUND OF THE INVENTION This invention relates to electric discharge devices, particularly of the type wherein the fill includes inorganic adduct molecules of niobium pentaiodide and inorganic oxo-compounds.

In copending patent application Ser. No. 229,933 filed Feb. 28, 1972, and assigned to the assignee of the present invention, there is described electric discharge devices which include, as the primary light-emitting component of the fill, a volatile oxytrihalide of a Group VB element, such as niobium. These devices have been shown to be exceptionally fine light generators, producing light of excellent quality and high efficiency. The molecular species Nb-O, when dissociated from the halogen of the niobium oxytrihalide in the arc of a discharge lamp, emits a dense line spectrum which lies predominantly in the visible portion of the spectrum, thus producing a light source with extremely desirable color characteristics. Niobium oxytrichloride and niobium oxytribromide have sufficiently high vapor pressures (at temperatures regularly achieved in such an arc lamp running under normal conditions) that there is no need either for external heating of the sealed envelope or for the mounting of the sealed envelope within an outer glass envelope. However, in order to minimize electrode transport problems, the moderately volatile niobium oxytriiodide is the presently preferred fill component for generating the molecular species Nb-O. The use of niobium oxytriiodide, however, has a drawback in that it decomposes to form relatively involatile niobium oxydiiodide and molecular iodine at slightly elevated temperatures. An arc lamp containing niobium oxytriiodide, therefore, has to be heated strongly to around 900C to produce the desired Nb-O molecular emission. This necessitates the use of external heating of the sealed envelope and, optionally, the mounting of the discharge device within an outer glass envelope.

It would, therefore, be desirable to provide an electric discharge device which makes use of an oxyiodide fill which yields the molecular species Nb-O, but does not require external means to heat the till to higher than normal operating temperatures while generating light of a desired and acceptable spectral quality.

OBJECTS OF THE INVENTION It is, therefore, an object of the present invention to provide a novel electric discharge device.

It is a further object of the present invention to provide an electric discharge device having a volatile active component which yields, during operation of the device, the molecular species Nb -O.

It is a further object of the present invention to provide an electric discharge device having a volatile active component which yields the molecular species Nb-O at normal operating temperatures whereby external means for increasing the temperature of the device is not needed.

It is a further object of the present invention to provide an electric discharge device which includes, as the primary active component, adduct molecules of niobium pentaiodide and an inorganic oxo-compound of a triiodide of a Group VA element or an oxocompound of a diiodide of a Group VIA element.

It is still a further object of the present invention to provide an electric discharge device which includes, as the primary active components of the fill, niobium pentaiodide, an oxygen yielding material, and a triiodide of a Group VA element or a diiodide of a Group VIA element.

These and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed disclosure.

BRIEF SUMMARY OF THE INVENTION These and still further objects of the present invention are achieved, in accordance therewith, by providing an electric discharge device having a sealed lighttransmissive envelope and a fill within the envelope; the fill including, as the primary active component, adduct molecules of niobium pentaiodide with an inorganic oxo-compound. Of particular interest are the oxytriiodides of Group VA elements and the oxy diiodides of Group VIA elements. Such adduct molecules can be conveniently generatedwithin the sealed envelope by an in-situ technique by mixing together, within the sealed envelope, equimolar quantities of niobium pentaiodide, an oxygen yielding substance, such as mercuric oxide, and a triiodide of a Group VA element or a di-iodide of a Group VIA element. Also of interest are the adducts of niobium-pentaiodide with sulfur dioxide or sulfur trioxide. This in-situ technique produces, during operation of the device, adduct molecules having the formula NbI -XO I, where X is a Group VA or Group VIA element, m is l, 2 or 3 and n is 0, 2 or 3. In operation, after an initial warm-up period ofa few seconds, the discharge assumes an intense pink-white color which is characteristic of the emission of the molecular species Nb-O, thus demonstrating that a highly volatile compound has been synthesized insitu. As indicated above, it is unnecessary to provide external heating or an outer glass envelope to maintain the discharge device at operating temperatures whereat the desired molecular emission is produced.

The envelope contains, in addition, to the adduct herein described, or the components which will yield adduct molecules during operation of the device, a small quantity of a noble gas, such as argon, to facilitate starting. In addition, mercury can be added in a conventional amount if it is desired to have a higher pressure discharge device with a lower operating voltage. Where mercuric oxide is utilized as the oxygen donatingmaterial, mercury will inherently be provided, during operation of the device since the mercuricoxide will dissociate to yield the desired molecular oxygen and will simultaneously yield mercury. Furthermore, other well known and conventional materials, such as thallium, sodium or cesium halides, such as, for example, thallium iodide, sodium iodide, and cesium iodide, as well as other materials including cesium oxide, thallium oxide, mercurous iodide, etc. can be added to the fill for their known purposes, for example, to lower operating voltages, adjust spectral output, etc. During operation, the pressure within the envelope is principally generated by the volatilization of the mercury with only a small contribution to the total pressure being made by the volatile complex herein described. It is presently contemplated that total pressure, at operational temperatures, will normally be in the range of about onehalf to about atmospheres, generally from about 1 to about 3 atmospheres. At these pressures, the partial pressure of the niobium complex material herein described will generally be on the order of about 2 torr to about 100 torr.

Because of the volatility of the primary active com ponent (i.e. the niobium pentaiodide adduct with an oxo-iodide), the discharge devices of the present invention do not require external wall heaters to maintain the adduct in a volatile state. This is a distinct advantage which not only reduces production cost and chance of earlier operational failure, but is achieved with excellent light output having excellent spectral characteristics. For example, efficiencies on the order of about 60 to 80 lumens per watt have been attained with these devices, while light of excellent quality is generated.

The sealed light-transmissive envelope is generally made of quartz, although other types of glass may be used, such as alumina glass or Vycor, the latter being a glass of high silica content. It is essential, of course, that the material selected for the enevelope and the materials utilized in the fill not adversely react with one another, or with reaction products that are produced during operation. The lamp further includes energizing means located either inside or outside of the envelope, depending on the type of energy applied for producing an electrical discharge inside the envelope.

DESCRIPTION OF SPECIFIC EMBODIMENTS Referring to the drawing, discharge device 10 includes sealed light-transmissive envelope 12 having main discharge electrodes 13 and 14 at opposite ends thereof. Electrodes 13 and 14, made ofa suitable material such as thoriated tungsten, are supported by lead-in wires 15 and 16, respectively and have a tungsten helix l7 and 18, respectively, at their interior ends. An auxiliary starting electrode 19, generally prepared of tantalum or tungsten, is provided at one end of envelope 12 adjacent to main discharge electrode 14, and comprises an inwardly projecting end of another lead-in wire 20. Each of the three current lead-in wires 15, 16 and 20 have their ends welded to intermediate foil sections 21, 22 and 23, respectively, of molybdenum which are hermetically sealed within pinched sealed portions 24 and 25 of envelope 12. The foil sections are very thin, for example, approximately 0.0008 inch thick, and go into tension without rupturing or scaling off when the heated envelope cools. Molybdenum or tantalum wires 26, 27 and 28 are welded to the outer ends of foils 21, 22 and 23, respectively, and serve to convey current to the electrodes inside envelope 12. Inside envelope 12, there is volume 29 in which the adduct molecules herein described are volatized, etc., during operation of device 10. v

In operation, the adduct molecules of the present invention dissociate completely into Nb atoms, NbO molecules, I atoms, oxygen atoms, etc. in the arc. Such dissociated components most probably exit only for fractions of a second in the hottest portions of the sealed envelope but recombine in the cooler sections of the envelope to regenerate the volatile adducts. The adducts diffuse into the discharge and dissociate, thereby beginning, once again, this cyclic dissociation and regeneration process. Unfortunately, the spaced electrodes are slowly transported due to the atmosphere containing both oxygen and halogen atoms. Thus, these devices can be operated on the order of up to about hours prior to electrode failure and, accordingly, are limited in the uses to which they may be put. During their lifetime, however, these devices are exceptionally fine light generators, producing light of excellent quality at moderate efficiencies. The electrode failure problem can be eliminated, however, by eliminating the spaced electrodes and replacing them with radio frequency or microwave discharge activators or energizers (not shown). With such energizers, the electrode transport problem is eliminated, whereby the devices can be operated for greater periods of time.

The following Examples are given to enable those skilled in this art to more fully understand and practice the present inventon. They shouldnot be considered as a limitation upon the scope of the invention but merely as being illustrative and representative thereof.

In Examples I X, the envelope utilized is a 400 watt shallow-press (S.P.) envelope made of quartz, having a diameter of about 2.3 cm, a length of about 6.0 cm, a length between electrode tips of about 5.3 cm, and a volume of about 17.8 cc.

The lamps of Examples I X have been aged" by running at their full-rated power for short periods of times, on the order of 2 to 18 minutes, after which period the characteristics identified in the Examples were measured without a cooling period.

When given in the following Examples, strike potential is defined as the peak AC voltage (with reference to the zero potential) required for lamp ignition, and

peak potential is defined as the peak AC voltage (with reference to the zero potential) after lamp stabilization when operated at its rated power.

EXAMPLE I EXAMPLE II A 400 watt S.P. envelope is filled with 8.1 mg Nbl 5.1 mg Asl 2.4 mg HgO, 51 mg Hg, and 23 torr argon. These components correspond to the chemical adduct formula NbI -As0I,,. When operated at 399 watts and 1.58 amps, the lamp had a strike potential of 2,400 volts,a peak potential of 3,200 volts, and an efficiency of 31 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE III A 400 watt S.P. envelope is filled with 8.1 mg Nbl 5.6 mg SbI 2.5 mg I-lgO, 50 mg Hg and 23 torr argon. These components correspond to the chemical adduct formula NbI -SbOI When operated at 400 watts and 1.45 amps, the lamp had a strike potential of 4,000 volts, a peak potential of 3,700 volts, and an efficiency of 60 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE IV A 400 watt S.P. envelope is filled with 8.1 mg Nbl 6.6 mg Bil 2.4 mg HgO, 50 mg Hg and 23 torr argon. These components correspond to the chemical adduct formula NbI 'BiOI When operated at 401 watts and 1.49 amps, the lamp had a strike potential of 4,000 volts, a peak potential of 3,550 volts, and an efficiency of 38 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE V A 400 watt S.P. envelope is filled with 8.1 mg Nbl 0.36 mg S, 5.1 mg Hgl 2.4 mg HgO, 48 mg Hg, and 23 torr argon. These individual components correspond to the chemical adduct formula NbI -SOI When operated at 345 watts and 1.53 amps, the lamp had a strike potential of 1,650 volts, a peak potential of 4,000 volts, and an efficiency of 28 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE VI A 400 watt S.P. envelope is filled with 8.1 mg Nbl 3.6 mg S, 5.1 mg Hgl 4.8 mg HgO, 46 mg Hg and 23 torr argon. These individual components correspond to the chemical adduct formula Nbl SO l When operated at 400 watts and 1.50 amps, the lamp had a strike potential of 2,200 volts, a peak potential of 4,000 volts, and an efficiency of 60 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE VII A 400 watt S.P. envelope is filled with 8.1 mg Nbl 3.1 mg HgSe, 5.1 mg Hgl 2.4 mg HgO, 46 mg Hg and 23 torr argon. These individual components correspond to the chemical adduct formula NbI -SeI When operated at 400 watts and 1.83 amps, the lamp had a strike potential of 1,400 volts, a peak potential of 2,300 volts, and an efficiency of 48 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE VIII A 400 watt S.P. envelope is filled with 8.1 mg Nbl 3.7 mg HgTe, 5.1 mg Hgl 2.4 mg HgO, 46 mg Hg, and 23 torr argon. These components correspond to the chemical adduct formula NbI -TeOI When operated at 412 watts and 1.55 amps, the lamp had a strike potential of 3,200 volts, :1 peak potential of 4,000 volts, and an efficiency of 78 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

In the following Examples IX and X, the adducts are of Nbl and a non-iodated oxide of sulphur.

EXAMPLE IX A 400 watt S.P. envelope is filled with a 8.1 mg Nbl 0.36 mg S, 4.8 mg HgO, 48 mg Hg and 23 torr argon. These components correspond to the adduct having the formula Nbl -SO When operated at 388 watts and 1.55 amps, the lamp had a strike potential of 1,900 volts, a peak potential of 3,400 volts, and an efficiency of 64 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pink-white color.

EXAMPLE X A 400 watt S.P. envelope is filled with 8.1 mg Nbl 0.36 mg S, 7.2 mg HgO, 46 mg Hg, and 23 torr argon. These components correspond to the adduct having the chemical formula Nbl 'SO When operated at 400 watts and 1.68 amps, the lamp had a strike potential of 2,600 volts, a peak potential of 4,000 volts, and an efficieney of 58 lm/w. After an initial warm-up period of a few seconds, the discharge assumed an intense pinkwhite color.

EXAMPLE XI In this Example light-emission is promoted by the microwave activation of the components of the fill within the sealed light-transmissive envelope. The envelope is made of quartz, is about 2.5 inches long, and about 0.75 inch in diameter. The ends are flat with one end having a side arm closely adjacent thereto. The end without the adjacent side arm is inserted into a waveguide. Approximately 1.3 inches of the length of the envelope is within the waveguide. Temperature adjustment and thus control of the amount of the active component in the fill, is by heating or cooling that portion of the envelope which extends out of the waveguide. Excess adduct is present, but definitive weight or concentration measurements of the fill are not taken.

The envelope is filled with Nbl HgO, P1 50 mg Hg and 23 torr argon. When operated at a temperature above about 240C and input power about 400 watts at a frequency of about 2.45 GHz, the discharge is pinkwhite.

EXAMPLES XII XIV Example X1 is repeated substituting Bi1 Sel and Tel respectively, for the P1 A similar pink-white discharge is attained.

The present invention is considered distinct and separate from the method described by Branden et al., Act. Chem. Scand., 17, 353 (1963) which describes the formation of a 1:1 complex between NbCl and POCl Although the authors of the aforesaid article teach that a volatile complex can be formed, they do not relate their activities to electric discharge devices, do not suggest the use of iodide complexes as herein proposed for use in electric discharge devices and, most importantly, because such materials were not used in electric discharge devices, they do not show light emission from the molecular species NbO.

While the present invention has been described with reference to specific embodiments thereof, it will be understood by those skilled in this art that various changes may be made without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, apparatus, process, or then present objective to the spirit of this invention without departing from its essential teachings.

What is claimed is:

1. An electric discharge device comprising a sealed light-transmissive envelope; a fill within said sealed envelope, said fill including, as the primary active component, an adduct of Nbl with an inorganic oxocompound, said adduct dissociating during operation of said electric discharge device to provide lightemission from the molecular species Nb-O; and energizing means for producing an electric discharge within said envelope.

2. The discharge device of claim 1 wherein said oxocompound is selected from the group consisting of sulphur dioxide and sulphur trioxide.

3. The discharge device of claim 1 wherein said oxocompound is an oxytriiodide of a Group VA element.

4. The discharge device of claim 1 wherein said oxocompound is selected from the group consisting of P01 AsOl SbOl and BiOl 5. The discharge device of claim 1 wherein said oxocompound is POI 6. The electric discharge device of claim 1 wherein said oxo-eompound is AsOl 7. The electric discharge device of claim 1 wherein said oxo-compound is SbOl 8. The electric discharge device of claim 1 wherein said oxo-compound is BiOl 9. The electric discharge device of claim 1 wherein said oxo-compound is an oxydiiodide of a Group VIA element.

10. The electric discharge device of claim 1 wherein said o'xo-compound is selected from the group consisting of SOl S 1 SeOI and TeOl 11. The electric discharge device of claim 1 wherein said oxo-compound is SO1 12. The electric discharge device of claim 1 wherein said oxo-compound is S0 1 13. The electric discharge device of claim 1 wherein said oxo-compound is SeOl 14. The electric discharge device of claim 1 wherein said oxo-compound is TeOl 15. The electric discharge device of claim 1 wherein said adduct is generated in-situ.

16. The electric discharge device of claim 1 wherein said adduct is generated in-situ by providing as a part of said fill, Nbl an oxygen donor and a triiodide of a Group VA element or a diiodide of a Group VIA element.

17. The electric discharge device of claim 1 wherein said adduct is present in a partial pressure from about 2 torr to about torr.

18. The electric discharge device of claim 1 wherein said fill further includes a small quantity of a noble gas.

19. The electric discharge device of claim 1 wherein said fill further includes a quantity of mercury.

20. The electric discharge device of claim 19 wherein said mercury is in a quantity sufficient to generate a pressure during operation of about one-half portion about 10 atmospheres.

21. The electric discharge device of claim 1 further including a pair of electrodes spaced within said envelope and capable of being connected, at those portion thereof extending outside of said envelope, to means for applying an electrical potential thereto.

22. The electric discharge device of claim 1 further including microwave activation means for causing Nb-O light-emission from said fill.

qgxgg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,748,520 July 24, 1973 lfetent No. Dated Inventor-(3) H. Graham Silver 4 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 55, change "volatized" to -vo1ati1ized--. Column 8, Claim 20, line 3, after "one-half" delete "portion" and insert --to--.

Signed and-sealed this 26th day of February 1974.

(SEAL). Attest:

EDWARD M.F LETCHER,JR. ;C MAEHALL DANN Attesting Officer Commissioner of Patents 

2. The discharge device of claim 1 wherein said oxo-compound is selected from the group consisting of sulphur dioxide and sulphur trioxide.
 3. The discharge device of claim 1 wherein said oxo-compound is an oxytriiodide of a Group VA element.
 4. The discharge device of claim 1 wherein said oxo-compound is selected from the group consisting of POI3, AsOI3, SbOI3 and BiOI3.
 5. The discharge device of claim 1 wherein said oxo-compound is POI3.
 6. The electric discharge device of claim 1 wherein said oxo-compound is AsOI3.
 7. The electric discharge device of claim 1 wherein said oxo-compound is SbOI3.
 8. The electric discharge device of claim 1 wherein said oxo-compound is BiOI3.
 9. The electric discharge device of claim 1 wherein said oxo-compound is an oxydiiodide of a Group VIA element.
 10. The electric discharge device of claim 1 wherein said oxo-compound is selected from the group consisting of SOI2, SO2I2, SeOI2, and TeOI2.
 11. The electric discharge device of claim 1 wherein said oxo-compound is SOI2.
 12. The electric discharge device of claim 1 wherein said oxo-compound is SO2I2.
 13. The electric discharge device of claim 1 wherein said oxo-compound is SeOI2.
 14. The electric discharge device of claim 1 wherein said oxo-compound is TeOI2.
 15. The electric discharge device of claim 1 wherein said adduct is generated in-situ.
 16. The electric discharge device of claim 1 wherein said adduct is generated in-situ by providing as a part of said fill, NbI5, an oxygen donor and a triiodide of a Group VA element or a diiodide of a Group VIA element.
 17. The electric discharge device of claim 1 wherein said adduct is present in a partial pressure from about 2 torr to about 100 torr.
 18. The electric discharge device of claim 1 wherein said fill further includes a small quantity of a noble gas.
 19. The electric discharge device of claim 1 wherein said fill further includes a quantity of mercury.
 20. The electric discharge device of claim 19 wherein said mercury is in a qUantity sufficient to generate a pressure during operation of about one-half portion about 10 atmospheres.
 21. The electric discharge device of claim 1 further including a pair of electrodes spaced within said envelope and capable of being connected, at those portion thereof extending outside of said envelope, to means for applying an electrical potential thereto.
 22. The electric discharge device of claim 1 further including microwave activation means for causing Nb-O light-emission from said fill. 